Sandel H-Taws nears certification

Sandel Avionics is concluding certification flight testing of its helicopter-specific terrain awareness warning system and plans delivery of the H-Taws shortly after FAA TSO approval and certification, which is expected by early April.

Company founder and president Gerry Block told AIN that with radio altitude and air data computer inputs it will meet or exceed performance of any current Taws for helicopters. Like previous Sandel instrumentation, the panel-mounted H-Taws is form, fit and electrically interchangeable with existing 3ATI indicators, including radar altimeter displays when installed in rotorcraft panels. Cost is $18,950.

On a recent flight from McClellan-Palomar Airport, the H-Taws demonstrated versatility and a variety of display modes with bright color, high-resolution, direct sunlight viewability and wide viewing angle that have become Sandel trademarks. Afterward, Block said the system’s impressive performance was obtained with “developmental software.”

Sales director Jerry Henry said the Sandel H-Taws has a $3,250 option for night vision illumination system display lighting with completely unrestricted daylight visibility. Another option will allow the H-Taws to act also as the primary TCAS or traffic advisory system display for an additional $980.

Calling it “the only fully self-contained TSO C194 and TSO C151c compliant H-Taws,” Block said Sandel has achieved its primary objective to virtually eliminate nuisance alerts. “Eliminating invalid alerts is much more complicated in the helicopter,” he observed, defining a valid alert as one that requires pilot action.

“We spent a great amount of time on the fixed-wing nuisance alert issue and we’ve tried to take that into the helicopter arena,” Block said. “We’ve been mostly active in the class-A fixed-wing area, so we’re taking all that technology into the helicopter, which has a different set of requirements.” The self-contained unit combines both H-Taws and ground proximity warning system (GPWS) functions in the 9.8-inch long 3ATI indicator.

The Sandel H-Taws will interface with any Waas-capable GPS and, with an air data computer, provide full class-A-equivalent reporting. Although radar altitude is not a TSO C194 requirement, where installed it can refine descent and hover alerting algorithms. Block noted that the H-Taws terrain map has “a very high resolution, 3 arc/sec. horizontal [300-foot grid],” with sharply defined regionalized obstacle databases.